Engine fuel control



ugrs, 1,950 H. DAvlDs 2,518,291'

` ENINE FUELCQNTROL Filed April 1, 194e 2 sheets-sheet 1 g Tw ZE 5w 7i 7 .74 82 ,94 i I V ,MV l@ t 6o 46 Z5, 78 y1 .J 8

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ATTORNEY Aug. s, 195o Filed April l. 194e H. DAvlDs 2,518,291

ENGINE vFUEL. CONTROL 2 Sheets-Sheet 2 IN1/EN TOR HANS DAV/D5 A TTORNEY Patented Aug. 8, 1950 UNI-'rrp STATES PA'rsNr )OFFICE Hans Davids,y Beloit, Wis., assignor to' Fairbanks, Y Morse & Co., Chicago, Ill., a corporation of Illinois Application April 1, 1946, SerialNo. 658,655.V Y'

-6 1Claims.

This invention is directed to internal combustion engines of the type. having a plurality of means for supplying fuel toI each cylinder and is particularly concerned with novel. and improvedv means for-v controllably regulating.l the action of suchfuel supply means in response to engine operation..

While the present improvements may, of course, be` availed of for use in a, number of. different', and varying.Y engine installations of. the so-called dual fuel feed type, it is peculiarly pertinent to. engines of the opposed piston Diesel type wheresuch-.engines areemployed as-'prime movers for railwayy work for example, or inany situation Where the prime mover is subjected to alternate periods of operationl under. loadand operation at no load or idling conditions. y

It is to be understood, therefore, that the invention may have wide appli-cation in the. art of controllable regulation of primefmovers. equipped with dual fuel supply means common with each cylinder, but for Apresent understanding ofr purpose the following description Will be devoted to an; exemplarydisclosure: which relates to; an opposed .piston type: Diesel engine foruse or application as a locomotive prime mover..

Optimum operating: conditions for an engine of the type above noted. are.- especially difcult of attainment when the load characteristics run to extremes, such as that which prevails'` in railway work; Such an engine, when. called. upon. to oper- 'atea at continuous full load conditions', may be made to operate effectively with dual= fuel supply means and with the .proper degree of mixing rwrbulence. for enicient results; But.v the same engine when reduc-:edA tov idling speed at. no` load- :ling or operating at low: speed' withlight loading will be. over supplied bythe fuel supply means due to mechanical and other difficulties inv obtaining eiiicient. fuel delivery action of: the. respective fuel sup-ply.` means when throttled. The over supply of. fuel is. wasteful, produces dilution of. engine `lubrication oil: inY the; crankcase and, more importantly, hazardous to safe operation the excessrfuelwhich. ndsits Way into, the crank- Y. case area. will in time accumulate in sufiicient amounts to; crea-te. ari-explosive. mixture. with the air therein. It. is. important then in adapting .Diesel engines of the.y opposed piston type to railway locomotive' usage, as switcher or transfer 'uni-ts, that thev fuel' supply means be arranged'to deliver a. volumeof fuel which can be utilized almost-completely and in keeping* with the loadcharacteristics imposed thereon". Accordingly, -i-t is a principal object of thev `engine of the. opposed" piston type such that the 2 1 obj :actionablev operating 4charaoteristi'cs .above expressed may be Qbviatedf A u It is an object alsoto provide improved control mechanism. which is responsive to engineI operaie tion for `regulating the engine` fuelsuppl'y means such that. less;v than all of the. fuelsupply means may be conditioned to.. maintain engine, operation at. cer-tain predetermined times and at other times all of the. fuel supply means may be brought into effective. operation, itbeing noted that I.in airnulticylinder engine having a, plurality of fuel supply means associated with veach cylinder the present object will be satised if. one or less than all O f the fuel supply means for. each cylinder is operated at. certain .Ytimesand at other times, all of thefuel supply-means are operated A further object of the invention resides .in the provision of novelv control mechanism which will operateY in a predetermined sequential manner to. maintain--fueldelivery tofeacb. ofthe cylinders of a, multi-cylinder engine from one or less than all` of the, fuel supply means. associated. with each cylinder whenthe. engine is operating at idling speed with noloadloratlow speed withlight. load', and will operate to cause fuel delivery from all of the fuel supply meansassociated. with each cylinder in substantially equal quantities. when the.. engine. is. operating at. increased speed Lip-t0 full load or,.. at. least, With` loads. greater vthan light. loads,

v Other objects and advantages will appear from thefollowing descrip-tion of `a preferred embodiment, of` the invention whichis disclosed inv the accompanying drawing, in which: -v

. lig` lis a. schematicillustration of an engine showing. the novel. and improvedcontrol mechanism, whichconstitutes. the basis of the present invention, in controlling association with. thefuel supply means. for each cylinder of an internal combustion engine, it, being. noted that only one engine cylinder has been indicated;

Fig. 21s. a View similar to that of the preceding illustration but having the control mechanism adjusted, in responseto governor action, to a control setting commensuratevvith low speed, no load or light load engine operation; andv Fig. 3. is. a graph-ical disclosure of the preferred operating characteristics for the. fuel supply means associated with any. onev of the engine cylinders and! in .which the quantity of fuel from at leasttwo fuel supply means connected. Witha common. engine cylinder has been plotted against control setting thereof for the full range of engine voperation. froinzero fuel delivery to maximum, the solid line A denoting the curve for one fuel supply means and the dotted line B denoting. the curve for` the other fuel supply means.

In the. drawing there. is shown in schematic form only such portions of a Diesel engine as Willserve. to aid. a full understanding of the invention. The engine may have a frame structure comprised, in part at least, of side plates III, an end wall I I and an end closure plate I2. The engine cylinders, such as the one indicated at I3, are each equipped with at least two airless type fuel injection nozzles I4 of substantially identical construction, respectively receiving fuel -under pressure through conduits I5 from separate fuel supply means or pumps I6 and I'I suitably mounted on frame deck plates (not shown) at opposite sides of the cylinder.

As a basis for further description of the operating elements and control function thereof, a. brief reference will be made to the characteristics of the fuel pumps here preferred, although they do not constitute per se, a part of the invention. Each pump is of a well known and commercially obtainable type having a constant stroke reciprocable plunger which can be angularly adjusted about its major axis to permit variable fuel cutoff settings. The pump I 6 is provided With a fuel cut-off control rack I8 for the purpose of varying the pump output between no fuel and full fuel positions as indicated by suitable index marks scribed on the rack surface in conjunction with a fixed pointer element I9 carried by the pump casing. Similarly pump II has a fuel cut-01T control rack 2Q so that its output may be varied between no fuel and full fuel positions, the same being indicated on the rack surface in conjunction with a fixed pointer 2| mounted on the pump casing.

While it is not believed necessary to show the usual type of pump plunger operating means, it will be appreciated by those skilled in the art that each pump will be driven from engine operated cam shafts so that fuel supplied to each pump via conduits 22 will subsequently be delivered under pressure and in the determined quantity through conduits I5 to the common combustion space of the cylinder I3.

Referring now to the disclosure of Fig. '1 as it relates to the form, construction and arrangement of parts in the control system, a suitable bracket 25 secured at the end wall I I of the engine frame supports a primary control lever `26 for pivotal movement about a vertically directed pivot element 21 engaging the lever in its centrally located boss 28. The primary lever has oppositely extending arms 29 and 30, which are, in the present example, of somewhat unequal lengths as measured from a point on the lever 26 perpendicularly opposite the center line of pivot element 2'I. Lever arm 29 also carries a feeler element or sequence control pin 3| adjustably, threadedly mounted in boss 32 on the lever arm, as by the integrally formed and enlarged screw element 33 and locking nut 34. The purpose of this sequence control pin will appear presently. Arm of the primary control lever 26 is formed with an extended boss 35 for the pivotal mounting of a secondary control lever 36, the latter lever having a similar boss 31 overlying boss 35 forconnection thereto by pivot pin 38. Thus it can be seen that the respective arms 29 and 30 of primary lever 26 swing about the axis of pivot pin 21, and

that the secondary lever 36 is swingable relative to, but supported on the arm 30 so that it may 4have a dependent as well as an independent motion.

With further reference to the secondary lever 36, it will be noted that its longer arm 40 is pivotally urged toward the arm 30 of the primary lever 26 by a resilient, or spring element 43 fixed to the arm 40 at pin 44 and to arm 30 at pin 45.

In an arrangement of this character, the secondary control lever 36 may be described as having an independent or lost-motion movement relative to the primary control arm. The purpose and effect of this arrangement will be described in more detail hereinafter.

Primary control lever 26 is operatively connected by its arm 29 with a longitudinally shiftable pump control rod 46 through an operating motion compensating link 41 which is pivoted to arm 29 at 48 and to rod 46 at 49. Thus pivotal motion of lever 26 is reflected in longitudinal motion of the control rod 46. As seen in Fig. 1, the rod 46 carries a drive tting 52 having an arm 53 which is suitably secured in driving relation with the end of the pump control rack I8. This fitting is sleeved on control rod 46 so as to be initially positioned thereon for a zero pump rack setting when the control rod 46 is fully retracted to an engine off position. With this condition satisfied, the set screw 54 may be tightened up to iix the drive fitting 52 in adjusted position upon the control rod.

The opposite end or arm 30 of the primary control lever 25 is pivotally connected at 56 to a push-pull link 51 of an engine driven governor carried by the frame plate I2 and indicated generally at 58. The governor 58 is adapted to move the link 5I in a direction to swing the primary control lever 26 in a clockwise direction about pivot 2'I to increase fuel and in the opposite sense to decrease fuel, all in response to engine operation.

It will now be evident that the fuel pump I6, or a bank or series of similar pumps in a multicylinder engine in which each thereof is drivingly connected to rod 46 by means of the type shown at 52, is directly and at all times adjusted and controlled by the governor 58 to increase or decrease its fuel delivery capacity in accordance with the engine speed and, hence, load imposed on the engine. The governor motion is transmitted to the control rod 46 through the action of the primary control lever 26 in the manner described above.

A second shiftable pump control rod 60 is provided for actuating the control rack 20 of fuel pump II. Specifically, the rack 20 is connected to the rod 6I) through the arm 62 of a drive tting 63 sleeved on the rod and secured in adjusted position by the set screw 64 such that when the control rod is fully retracted the pump rack will be at its no fuel position or zero index. The inner end ofthe control rod 60 is pivotally connected through an operating motion compensating link 65 to the arm 66 of the secondary control lever 36. Pivot elements 61 and 68 serve to interconnect the last described parts in the manner shown.

The operation of the mechanism above described results in a selective or sequential control of fuel pump I'I for at times maintaining the same out of phase with fuel pump I6 and at other times conditioning the same for adjustment into a substantially equal control phase depending upon a condition of independent or dependent motion of the secondary control lever 36 relative to the primary control lever 26 as Will now be described. This condition of operation is innccord with an expressed objective of the present invention and is obtained in the following manner: Assuming that the control system with the engine shut olf is held by the governor 58 in its off position, it will be observed that the secondary lever 36 is in a displaced or angular position relative to primary aardgas control lever 26"'such that' the pump-rack 10 is'at its zero` position and the construction and initial relation of the mechanism'forcesA thefcontfrol lever 35`t`o` pivot against the spring 43. It is also' noted that theI pump-rack |81' isA in' its zerolposition. Now as the engine starts up= under no load but does not Iexceed a' speed commensurate withnoload or light loads; thegovernorv willrespond by mov'- i'ng push-pull link 51'V outwardly to a predetermined position corresponding with engine1 speed. This motion or link 5l :swingsv the primary control" lever 26 clockwise as i`n Fig; 2; such that the fuelf pump I6 wil'l have` its rackA I8" movedi to or closely adjacent the-index mark 3', forv example. During this initial' predetermined movement of primaryk control-l l'ever 26 the" secondary control lever 36 will' be' moved" through' its' pivotalV connection at boss 35' on lever 26", but by the action of the resilient element or spring 43 the said" lever ,36 is constantly urged in a counter clockwise direction'; This tends to' urgethecontrol rod 60 in a direction tov maintain no fuel. delivery" by pump il, and' as a result the secondary' lever 36 will swing in its' independent' or` lost motion relation to' a position alongsidek the` primary control lever. Thus, no advance oi" the control' rod 60 forfuell pump |11 can occur; When thesen condi*- tionsI arel met', the' engine is being supplied with fuel from the; pump' l6` alone, and. pump: IT' is maintained or remains ineffective and outl of phase;

In the present example itis preferredto ar'- range and adjust thel over all control mechanism forV attainingv just such a condition as has been described; As a consequence thereof', only one pumpof the dualv fuel supply meansfis initially operative to start and continue engine operation up to'say, i'dlingspeed orslightly'hi'gher and' with no load. or light" loads imposed' on the engine.A

Now should a load be imposed on' the engine, the governor will immediately respond by moving link 5'! ina fuel increasing direction. Primary control lever 26 will: be moved farther in a clock.`- wise direction, whereby to advance control" rod et and increase' the fuel delivery output of pump t5. Incident to this motion of the primary lever 2E, secondary control lever 36 will nov longer have relative liostmotionbut will attain' a condition of dependent motion relative to the lever 26' through theenergization ci a sequence control type'oillui'd interlock device; generally indicated' atY 1l?. When this interlocking devicei's energized it will prevent further independent movement ci' the secondary control lever 3G and simultaneously shift the latter to' a position in which' the fuel pumpy il is synchronized withor brought into substantially equal fuel output control phase with the' fuel pump IG. Thereafter the two fuel' pumps will remain in phasel for load increases on the engine.

It isA important to point out that the respective fuel' pumps are effectively maintained inphase due to the proportioning of the severalarm lengths of the levers 26- and 3E; For example, it is preferred tol have the length of.A arm 29" on primary- 6 fluid interlockA device is energized as will now be described.

The iluid interlock device 'FE1 comprises a housing 'll having a cylinder 'l2 at one-endl and a valve chamber T3 at its opposite end, the' cylinder and chamber being in constant communication through a small passage Mi. The housing' is mounted on the end' wall H- of the engine frame with the cylinder axis in alignment with the arm 40' on control lever fili such thatl a piston 115" movably positioned` in the cylinder may have its rod 15, projecting' outwardly or a Vented cylinder cap ll', movable into abutment' with the arm ai? atcertain times and such that the` armllll may abut the piston rod end at othertimes. When this il'uid device is not energized the piston is free to move inwardly of the cylinder where it bottoms on a boss H9 to preventclos-ure of the passage 'M'. At the opposite end of the housing ll, the valve chamber is provided with a cap i8 having' a port 80; a ball valve element 8l and a spring 82' adapted normally to urge the ball ele'- ment into port closing position against the cap. This device is', byl preference, supplied with fluid under pressure, through fitting 83 threadedv into the housing and in open communication with the valve chamber 13 through passage 84'. In'the present example a conduit 85 from the engine lube-oil system (not shown) is connected at iltw ting 83'.

In operation the duid: interlock device will at times direct pressure iluid to the cylinder l2, as when the port is closedV by ball 8l, to force rthe piston outwardly. However, when the ball valve` element is unseatedl fluid: will' immediately ii'ow through the portedcap and relieve iiuid pres sure in cylinder 12k. Fluid ilcwvingA through the port'` till in cap T8' is by any' suitablev means (not sl'lownlv returned tothe engine cranscase. Acccrding to a preferred construction the liu-id passage 'laA is ofv small bore to offer' resistanceV to ilowvsuclfll that the4 outward movement of the piston l5 is gradual and thus does not cause a sudden movement of lever 35, which would tend to overload theV .governorv 58'.

Energization of the fluid interlock device is controlled in timed relation with movement of primary controly lever 26- by the sequence conftrol pin element tl carried by the lever in the manner before noted. In the present example, the pin 3 lv is pfositiona-lly` adjusted such that it will .maintain the ball valve 8l in port open position until arm 29' of primary control lever been movedin a clockwise direction for regulating pump I5: to increase its fuel output, and where additional fuel is required to operate the engine, commensurate with load increases above idling or light loadcond-itions. As this condition of engine operation is attained, the ball valve- 8l willI close port' 30: cutting off escape of iiuidand thus causing the grad-ualfbuild-up oi pressurefin cylinder l2 through thellow restricting passage 'M to move piston 15 outwardly ofthe cylinder such thatA pistonrod 'F6- abuts the arm liti on secondary control loveriiy to swing the latter in a clockwise direction intoan angular position such that thev con-- trol rod` 6l!A is advanced to move rack 2li@ at fuel pump Il. The motionv imparted tothe secondary 751m'- it 'will be apparent that the secondary control lever 36 is prevented from independent motion, and hence, may be described as dependent for its further movement upon motion of the primary control lever 26.

When the load on the engine decreases or its speed is decreased to or below the light load or idling condition the fuel pumps IB and il will be simultaneously throttled through the concurrent motion of the primary and secondary control levers until the sequence pin 3l again is positioned to lift the ball valve 8| away from port 80. At such latter time, the lost motion take-up spring i3 between the control levers 25 and 36 will urge the piston l5 inwardly as the fluid pressure thereon gradually drops to a Zero value or becomes inconsequential due to effective pressure relief at port 80. Control lever Se will thereupon be moved by the spring in a counterclocxwise direction to shift pump control rod 5E and pump rack 2i? to its no fuel position, hence cutting off further fuel delivery by pump il. Continued throttling action by governor 58 will swing primary control lever 26 in a counter clockwise direction and concurrently will cause the secondary control lever 3G to move relatively and in a clockwise sens-e, as the pump control rod Gli is prevented from further retraction by reason of the pump rack 2Q having reached the inner limit of its stroke. As a result, the arm fifi will move out of abutment with the end of piston rod f5 and at engine shut down the secondary lever 36 will again be displaced or angularly related with respect to the primary lever 26, as in Fig. 1.

Turning to Fig. 3, the graph illustrates the respective functions of the pump I6 (in solid line A) and pump il (dotted line B) over the full speed and load range of the engine up to 100 percent load. The rack positions indicated by the graph are also to be found on the respective pump rack members I8 and 28. As shown by the graph, the preferred pump operating phases require pump le to deliver fuel at all times and pump Il to begin or terminate fuel delivery at or close to engine idling speed with no load or light loads. This latter condition is attained at or close to position 3 on rack I8, at which position the pump l1 is almost immediately shifted to deliver fuel substantially equally with pump l5 on the sharply rising dotting line curve, or to cease fuel delivery if the control mechanism is shifted to decrease fuel. For engine operation at greater than light loads, both fuel pumps will deliver substantially equal quantities of fuel, hence the two curves A and B above rack position 3 are superposed.

However, it should be understood that the actual quantity of fuel delivered is equal to twice the value of any given ordinate, except for rack positions below that at which the dotted line curve B drops to a Zero valve.

As a consequence of the preferred pump operating phases, each cylinder of the engine will be supplied initially with fuel from only one pump at such times as it is deemed desir-able to limit fuel delivery for the expressed purpose of preventing fuel wastage, crankcase oil dilution and dangerous accumulations thereof within the engine crankcase. The exact point at which the engine is to be operated by less than all of the fuel pumps associated with each of the cylinders will depend on the fuel consumption characteristics within the idling speed range with no load or light loads. However, the critical operating range is normally limited and hence requires only small governor responsive movement to shift pump l1 into or out of operative fuel delivery relationship with pump i6. The advantages for such a system of pump control will at once, become evident when it is considered that Diesel engine powered locomotives may have extended periods of operation at idling speed with no load or light load.

It will now be fully apparent that the objectives of the present invention are effectively carried into practice through the functioning of the above described control mechanism, and that the objectionable and hazardous operating characteristics of prior dual fuel systems are entirely obviated in a simple, direct and positive manner. Further discussion of the presently preferred form, construction and arrangement of operating means, elements and agencies for accomplishing the desired results is believed unnecessary, as the foregoing detailed description will provide sufficient basis to those skilled in the art for understanding the underlying principles hereof.

It should be noted, however, that each of the important control elements, such as the sequence pin 3|, and drive fittings 52 and 63 respectively, are adjustable in character so that initial assembly adjustments may be made for attaining proper control results; and as the control system exhibits a certain amount of unavoidable wear and loosening, these important elements may be readjus'red to restore the proper control.

It is also obvious that the effective stroke of the piston l5 may be varied according to the desired setting of the control lever 3S by the use of shims (not shown) under the vented cap 'l1 whereby the piston may have greater or less travel within the cylinder bore. The use of shims, spacers or the equivalent is well understood in the art and requires no detailed disclosure beyond the fact that their use is contemplated herewith.

Certain refinements, as well as obvious modifications, substitutions of eduivalentparts and a1- terations in form', assembly or construction hereof, may be suggested from an understanding of the presently preferred system. However, it is intended that all such refinements, substitutions and modications shall be included within the scope of the invention as the same is defined by the annexed claims.

What is claimed is:

l. Fuel pump control mechanism for an internal combustion engine having at least two adjustable output fuel pumps in fuel delivery association with a common combustion Zone of the engine; said mechanism including shiftable means operably connected one to each fuel pump for adjusting the fuel output thereof, pivotally connected and relatively movable cooperative elements operably connected one with each of said shiftable means, said elements being connected and arranged for relative lost-motion movement thereby permitting fuel output adjustments of one fuel pump relative to the other fuel pump during a predetermined initial range of movement of one element, and a control device positioned adjacent said cooperative elements so as to be operated in response to said predetermined movem'ent of one thereof for causing conjoint operation of said cooperative elements whereby to effect concurrent fuel output adjustments of each fuel pump, said device comprising a pluger fluid pressure urged in a direction to cause conjoint operation of said elements, and a pressure fluid control valve movable in response to said one element, said valve attaining a setting to direct pressure fluid to said plunger upon said predetermined movement of said one element.

2. Fuel pump control mechanism for an internal combustion engine having a cylinder and at least two adjustable output fuel pumps operated by the engine and connected in fuel delivery association with the cylinder combustion space; said mechanism including separatev shiftable means connected with each of the fuel pumps for adjusting the fuel output thereof, a first control element connected to one of the shi-ftable means for adjusting the fuel output of thefuel pump connected thereto, a second control element connected to the other of said shiftable means, said second element being carried by said first relement for lost-motion movement relativeto the latter during a predetermined initial fuel adjusting movement of the latter, and a control device operatively positioned adjacent saidA control elements so as to be responsive to the predetermined initial movement of said first control element, for preventing further lost-motion'm'ovement of said second control element whereby said fuel pumps are simultaneously adjusted as to fuel output, said device having an element movable into abutment with the second controlelement and means for controlling the movable element.

3. Fuel pump control mechanism for an internal combustion engine having at least two adjustable output fuel pumps in fuel delivery association with a common combustion zone of the engine; said mechanism including fuel output adjusting means for each of the fuelrpumps, a first control lever pivoted on the engine and co-nnected at one end to one of said adjusting means, an engine operated governor connected at the opposite end of said first lever for pivoting the latter to cause fuel output adjustments: of the fuel pump associated therewith, a second control lever independently pivotally mounted on said first lever and connected at one end tothe other of said adjusting means, resilient means operatively connected between said flrst and second levers in a manner to urge the other of said fuel pump adjusting means connected'to said second lever in a fuel output decreasing direction for a predetermined initial governor urged movement of said first lever to move said one? fuel pump adjusting means in a fuel output increasing direction, fluid pressure responsive means on the engine positioned adjacent said first and second levers, said last means having a' piston displaceable by fluid pressure in a direction to move said second lever in opposition to said resilient means and a pressure relief valve normally urged toward closed position for permitting piston displacement, and means on said first control lever normally adapted to maintain said valve in open position to prevent piston displacement, but movable with said first lever such that said vvalve closes upon attainment of the predetermined initial movement of said first lever whereby said piston is displaced to move said second lever and the other of said fuel pump adjusting means connected thereto in a fuel output increasing direction.

4. Fuel pump control mechanism as set forth in the preceding claim' and in which displacement of said piston is effective to move said second lever and the other of said fuel pump adjusting means connected thereto in a fuel output increasing direction such that each of the fuel pumps is adjusted for substantially equal fuel output.

5. Fuel pump control mechanism for an engine having two adjustable output fuel pumps in com munication with a common combustion zone of the engine; said mechanism including first and second control levers relatively movably interconnected and respectively connected in fuel output adjusting relation with a first and a second fuel pump, engine operated governor means operatively connected to move. the first lever for adjusting the first fuel pump between no fuel and full fuel delivery conditions, resilient means connected between said levers and acting on the second lever to maintain the second fuel pump substantially at a no fuel delivery adjustment during at least an initial fuel delivery adjustment range of the first fuel pump, and a controllable fluid pressure energized interlock device adjacent said levers for opposing said resilient means to move said second lever for adjusting the second fuel pump into a fuel delivery condition in response to movement of the first lever in a fuel increasing direction beyond the said initial fuel delivery adjustment range of the first pump, said interlock device having a fluid pressure source and providing a fiuid pressure urged element abuttable with the second lever, and a control valve normally movable to closed position for supplying pressure fluid to move said element, the valve being positioned for opening actuation by the first lever during the initial fuel delivery adjusting range of the first fuel pump.

6. In an internal combustion engine having a cylinder providing a, combustion space to which fuel is supplied by a pair of controllable output fuel pumps; the combination therewith of means comprising a first control lever operatively connected to one fuel pump for regulating its output in response to engine fuel demands, a second contr-ol lever operatively connected to the other fuel pump for regulating its output, said second lever being pivotally connected to the first lever for imparting bodily movement to the second lever upon movement of the first lever, resilient means acting on the second lever to pivot the same relative to the first lever and in a direction to maintain said other pump in a no fuel output regulation during a predetermined initial range of fuel output regulation of saidv one pump, and an in' erlock device adjacent said levers for effecting relative pivotal movement of the second lever against said resilient means to regulate the fuel output of the other pump toward substantially equal output with said one pump and for interloclzingl said levers such that the seco-nd lever is bodily movable with the rst lever, said device being of controllable fluid pressure character having a fluid pressure source and providing a pressure urged element engageable with the second lever, and a control valve normally movable to closed position for supplying pressure fluid to move said element, the valve being located so as to be Vactuated to an open position by the first lever dus# ing its predetermined initial range of regulation. HANS DAVIDS.

REFERENCES CITED The following references are o f record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,676,827 Howard et al July 10, 1928 2,010,469 Triebnigg Aug. 6, 1935 2.221.405 Nallinger Nov, 12, 1940 

